DraftKings isn't just pitting contestants against each other in fantasy NFL football -- the online weekly challenge is minting millionaires and expanding to basketball, golf, and mixed martial arts.

NEW YORK (TheStreet) -- Fantasy competition site DraftKings has already made 10 millionaires this year, and it will pay out even more before this year's NFL season comes to an end.

Next, says CEO Jason Robins, it may mint millionaires off the fantasy gridiron, too. Robins thinks it will take "one more mega-round" of venture financing to bolster his Boston-based brainchild's operations, and that an IPO could come in as little as two years, in 2016.

"We have an international road map we're working on," he told TheStreet.

This year, DraftKings soared past its projections of $200 million in prize payouts as fantasy fans flocked to the site to test their luck against experts like Drew Dinkmeyer, a Florida man who used to work in finance until he pursued his dream to a $1 million payday this past Monday night. That's significant for DraftKings, since the company takes about 10% of prize payouts for the bulk of its revenue. At $300 million in prize payouts, that puts the company's 2014 revenue at about $30 million. With projections to hit $1 billion in payouts next year, Robins suggested the company could have $100 million in revenue at the end of 2015.

Robins' team is relatively small -- 121 employees -- and DraftKings has yet to reach profitability, he told TheStreet, since the company is focusing on growth. Already, DraftKings has paid its top $1 million prize to Dinkmeyer and nine other skilled online players; more typical top prizes stretch into the tens -- and occasionally hundreds -- of thousands of dollars.

The concept is simple, and familiar to season-long fantasy football players, who are far greater in number than weekly challenge players. Players pick a lineup and the site tracks and awards points based on their fantasy team members' individual accomplishments that week. With DraftKings and other weekly challenge sites, once the fantasy week ends, prizes are awarded.

Right now, DraftKings focuses primarily on U.S. sports -- not just the National Football League, but the National Basketball Association, Major League Baseball, even the Professional Golfers' Association -- but that U.S. focus will soon change, Robins said.

"International is one of the most compelling long-term opportunities for us," he said, adding that "going into the U.K. is going to be a lot simpler than going into India" because of language and other issues.